Masking issues with Motion 5

Question

Hi guys,
I had this general masking technique that I used with Motion 4 where I'd use any group of shapes, paintstrokes and so on, to mask some other object by dragging my group of "mask objects" into the image mask source well.
This technique no longer works as expected with Motion 5.
As an example, consider this project where I want to gradually reveal a circle.
Below are screen shots from both Motion 4 and Motion 5 of the same project, at frame 10:
As you can see, Motion 4 gradually unveils the masked shape (a circle), but Motion 5 doesn't.
I could get around this particular case by adding a write on behaviour to the circle shape. BUt this does not work as a general masking technique in M5, which is a bit sad.
Anyone care to shed some light?
BR;
::e

Answer 1

Hi Chand+Mark
Chandosx wrote:
You could get away with it by setting the blending mode to stencil alpha, but that won't work in every situation.  The other thing you could do, is place the layer that's the source of the mask at the very bottom of everything, so it's not shown, and leave the layer turned on.  Then all should work sorta the same.  Quirky.
I'm not really familiar with what stencil alpha does, so I can't comment on that.
But the bottom layer option won't be any good if you want partially transparent output.
It *will* show unless you have some layer covering it up, which would be purely coincidential
UNLESS you use one very very special color for the mask source shape, and send the whole shebang through the keyer to get your alpha channel proper
Chandosx wrote:
And one other way I just tested, that works for sure, is using keyframes on the source shape's "First Point Offset"(or last ).
Hey, a self-made "write-on" for the mask source shape?
Well, it works in M4 - I'll confirm with M5 tomorrow.
Thanks for all your efforts to figure this out!
I still certainly consider this a bug and would expect this to be fixed.
How can I go ahead and report this a bug to Apple, are they monitoring this forum?
Cheers!
::e